Page 1 of 98
Arizona CR-21 Sprinkler Irrigation Systems EXAM QUESTIONS
AND CORRECT VERIFIED SOLUTIONS LATEST UPDATE THIS
YEAR – JUST RELEASED
Arizona CR-21 Sprinkler Irrigation Systems Exam
10-Line Exam Coverage in Points Form
1. License Authority – The Arizona Registrar of Contractors (ROC) issues the CR-21 license
via PSI Services. This dual license covers residential and commercial hardscaping and
pressurized irrigation systems .
2. License Scope – CR-21 permits installation, repair, and maintenance of hardscape
features (pavers, retaining walls up to 3 feet, outdoor fireplaces) and pressurized
irrigation systems (sprinklers, drip systems, backflow preventers) .
3. Exam Structure – Candidates must pass both the Business Management (SRE) exam and
the CR-21 Trade Exam. The trade exam covers plan reading, soil preparation, drainage,
masonry standards, and hydraulic principles .
4. Core References – Primary reference materials include OSHA 29 CFR Part 1926,
International Plumbing Code (IPC), and landscaping/irrigation manuals .
5. Hydraulic Principles – Pipe sizing is determined by required flow (GPM) and acceptable
friction loss; maximum recommended water velocity in PVC mainlines is 5 ft/s to prevent
water hammer .
6. Backflow Prevention – Reduced Pressure Zone (RPZ) assemblies provide the highest
protection for potable water. PVB must be mounted at least 12 inches higher than the
highest downstream sprinkler head .
7. Excavation Safety – Contact 811 (Blue Stake) before any digging; use white paint to mark
proposed boundaries. OSHA requires protective systems for trenches 5 feet or deeper .
8. Drip Irrigation – Pressure regulators reduce pressure to 10–30 psi to protect emitters.
Emitter clogging is most commonly caused by fine sand or silt in the water supply .
9. Water Conservation – Hydrozoning groups plants by similar water needs. Soil moisture
sensors adjust watering based on real-time soil water content to conserve water .
10. Applicator Experience – CR-21 requires a minimum of four years of hands-on or
managerial experience in the field .
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Practice MCQs with Rationales
1. Which component controls the start and stop timing of irrigation cycles?
A) Master valve
B) Solenoid valve
C) Controller
D) Pressure regulator
Answer: C
Rationale: The controller is the electronic device that programs start times, cycle lengths, and
days of operation for the irrigation system. It serves as the "brain" of the system, coordinating
valve operation and scheduling watering events .
2. In a drip-irrigation system, the primary purpose of a pressure regulator is to:
A) Increase flow to match emitter demand
B) Reduce pressure to prevent emitter damage
C) Eliminate air from the line
D) Filter out sediment
Answer: B
Rationale: Drip emitters are designed for low pressure (typically 10–30 psi); a pressure regulator
reduces line pressure to protect emitters and ensure uniform flow. Without pressure regulation,
emitters can be damaged or deliver inconsistent output .
3. What is the recommended maximum water velocity inside a PVC irrigation mainline to
prevent damaging water hammer surges?
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A) 2 feet per second
B) 5 feet per second
C) 8 feet per second
D) 10 feet per second
Answer: B
Rationale: Industry standards dictate that water velocity should not exceed 5 feet per second in
plastic pipes to minimize pressure surges and water hammer risks. Higher velocities can cause
pipe damage and fitting failure .
4. Which type of backflow preventer provides the highest level of protection for potable
water?
A) Atmospheric vacuum breaker (AVB)
B) Pressure vacuum breaker (PVB)
C) Reduced pressure zone (RPZ) assembly
D) Double check valve assembly (DCVA)
Answer: C
Rationale: RPZ assemblies have two check valves and a pressure-reducing chamber, protecting
against both back-pressure and back-siphonage. This provides the most stringent protection
level required for high-hazard applications like chemical fertigation .
5. When installing a Pressure Vacuum Breaker (PVB) assembly, how high must it be mounted
relative to the highest downstream sprinkler head?
A) 6 inches
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B) 12 inches
C) 18 inches
D) 24 inches
Answer: B
Rationale: Plumbing codes state that a PVB must be installed at least 12 inches higher than the
highest downstream piping, outlet, or sprinkler head it protects. This ensures proper operation
and prevents back-siphonage .
6. What is the minimum slope required away from a building foundation for proper drainage?
A) 0.5%
B) 1%
C) 2%
D) 5%
Answer: C
Rationale: Arizona code and best practices call for at least a 2% slope (¼ inch per foot) to direct
water away from foundations. This prevents water intrusion and protects structural integrity .
7. Which sensor is most effective at preventing irrigation during windy conditions?
A) Soil moisture sensor
B) Rain sensor
C) Wind sensor (anemometer)
D) Light sensor
Arizona CR-21 Sprinkler Irrigation Systems EXAM QUESTIONS
AND CORRECT VERIFIED SOLUTIONS LATEST UPDATE THIS
YEAR – JUST RELEASED
Arizona CR-21 Sprinkler Irrigation Systems Exam
10-Line Exam Coverage in Points Form
1. License Authority – The Arizona Registrar of Contractors (ROC) issues the CR-21 license
via PSI Services. This dual license covers residential and commercial hardscaping and
pressurized irrigation systems .
2. License Scope – CR-21 permits installation, repair, and maintenance of hardscape
features (pavers, retaining walls up to 3 feet, outdoor fireplaces) and pressurized
irrigation systems (sprinklers, drip systems, backflow preventers) .
3. Exam Structure – Candidates must pass both the Business Management (SRE) exam and
the CR-21 Trade Exam. The trade exam covers plan reading, soil preparation, drainage,
masonry standards, and hydraulic principles .
4. Core References – Primary reference materials include OSHA 29 CFR Part 1926,
International Plumbing Code (IPC), and landscaping/irrigation manuals .
5. Hydraulic Principles – Pipe sizing is determined by required flow (GPM) and acceptable
friction loss; maximum recommended water velocity in PVC mainlines is 5 ft/s to prevent
water hammer .
6. Backflow Prevention – Reduced Pressure Zone (RPZ) assemblies provide the highest
protection for potable water. PVB must be mounted at least 12 inches higher than the
highest downstream sprinkler head .
7. Excavation Safety – Contact 811 (Blue Stake) before any digging; use white paint to mark
proposed boundaries. OSHA requires protective systems for trenches 5 feet or deeper .
8. Drip Irrigation – Pressure regulators reduce pressure to 10–30 psi to protect emitters.
Emitter clogging is most commonly caused by fine sand or silt in the water supply .
9. Water Conservation – Hydrozoning groups plants by similar water needs. Soil moisture
sensors adjust watering based on real-time soil water content to conserve water .
10. Applicator Experience – CR-21 requires a minimum of four years of hands-on or
managerial experience in the field .
, Page 2 of 98
Practice MCQs with Rationales
1. Which component controls the start and stop timing of irrigation cycles?
A) Master valve
B) Solenoid valve
C) Controller
D) Pressure regulator
Answer: C
Rationale: The controller is the electronic device that programs start times, cycle lengths, and
days of operation for the irrigation system. It serves as the "brain" of the system, coordinating
valve operation and scheduling watering events .
2. In a drip-irrigation system, the primary purpose of a pressure regulator is to:
A) Increase flow to match emitter demand
B) Reduce pressure to prevent emitter damage
C) Eliminate air from the line
D) Filter out sediment
Answer: B
Rationale: Drip emitters are designed for low pressure (typically 10–30 psi); a pressure regulator
reduces line pressure to protect emitters and ensure uniform flow. Without pressure regulation,
emitters can be damaged or deliver inconsistent output .
3. What is the recommended maximum water velocity inside a PVC irrigation mainline to
prevent damaging water hammer surges?
, Page 3 of 98
A) 2 feet per second
B) 5 feet per second
C) 8 feet per second
D) 10 feet per second
Answer: B
Rationale: Industry standards dictate that water velocity should not exceed 5 feet per second in
plastic pipes to minimize pressure surges and water hammer risks. Higher velocities can cause
pipe damage and fitting failure .
4. Which type of backflow preventer provides the highest level of protection for potable
water?
A) Atmospheric vacuum breaker (AVB)
B) Pressure vacuum breaker (PVB)
C) Reduced pressure zone (RPZ) assembly
D) Double check valve assembly (DCVA)
Answer: C
Rationale: RPZ assemblies have two check valves and a pressure-reducing chamber, protecting
against both back-pressure and back-siphonage. This provides the most stringent protection
level required for high-hazard applications like chemical fertigation .
5. When installing a Pressure Vacuum Breaker (PVB) assembly, how high must it be mounted
relative to the highest downstream sprinkler head?
A) 6 inches
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B) 12 inches
C) 18 inches
D) 24 inches
Answer: B
Rationale: Plumbing codes state that a PVB must be installed at least 12 inches higher than the
highest downstream piping, outlet, or sprinkler head it protects. This ensures proper operation
and prevents back-siphonage .
6. What is the minimum slope required away from a building foundation for proper drainage?
A) 0.5%
B) 1%
C) 2%
D) 5%
Answer: C
Rationale: Arizona code and best practices call for at least a 2% slope (¼ inch per foot) to direct
water away from foundations. This prevents water intrusion and protects structural integrity .
7. Which sensor is most effective at preventing irrigation during windy conditions?
A) Soil moisture sensor
B) Rain sensor
C) Wind sensor (anemometer)
D) Light sensor
